TORRENTIAL rain, thunder and lightning hit Dorset today causing severe flooding and travel chaos.

The A338 Wessex Way was partially blocked by flooding all the way from County Gates to Cooper Dean, while parts of Castle Lane were under 2ft of water.

Severals sewers have overflown and all the beaches in Poole and Bournemouth have been red flagged by the RNLI as a public health precaution.

Volunteers have offered to help Bournemouth Council clear the debris clogged gardens. Officers have thanked them but think they can do the job without help working from 5am.

The River Avon is expected to burst its banks tonight between Ringwood and Christchurch.

There were reports of the road splitting after a manhole cover came up. Drain covers have also reportedly been lifted up across the county.

Parts of Wimborne Road, Exeter Road, Wellington Road and Magna Road were blocked because of the weather and broken-down vehicles.

Bournemouth’s Lower and Central Gardens and Boscombe Gardens were both in deep floodwater during the storms, which saw thunder and lightning as well as heavy downpours at around 10.30am.

Police closed Braidley Road to St Stephen's Road and one of their own vehicles was stuck and then towed free around 11.45am.

Heavy rain and flash-floods were affecting roads across the county, with police reporting floodwater up to the level of car bonnets.

The Russell-Cotes museum was forced to close as a result of flooding.

Bystander Christopher Brooker, 20, said: “I’ve never seen anything like this, it’s just incredible. It’s just freak weather. It’s the curse of the Air Festival.

“I’ve seen the odd puddle or two, but nothing like this before, it’s unprecedented. I’m just shocked.”

Martin Heath, 25, a part-time kitchen worker, from Springbourne, said: “I haven’t seen rain like that for ages, it was tropical. It was just incredible. It didn’t stop coming. I haven’t seen anything like this for years.”

Boscombe Pier was hit by overflowing sewage and floodwater strong enough to wash away part of the beach.

Witnesses said water poured down steep Sea Road and Boscome Gardens reaching a peak around 11am.

Footage by Paul Godier

The water cascaded over the promenade in a 40ft long waterfall that scoured away tonnes of sand carved five channels to the sea up to 4ft deep.

Mark Dibben, 36, from Christchurch, said: 'It was so powerful it was holding back the waves.

"The guy in the booth by the entrance to the prom was stranded for 45 minutes.

"All the sewerage drains in the area were popping up."

The water flowing down Sea Road was 4-5 inches deep and mixed with plant debris and sewerage that could be smelt where it had built up around obstacles.

Jenna Westwood, from the Mercedees promotional team, said: "The water was gushing down like a river.

"The water was smelly.

"We tried to set up but it was impossible and the beach was empty."

Another bout of heavy rain and lightning from around 12.45pm to 1.15pm led to a second, though much smaller outbreak of floodwater in the same areas.

Poole's Dolphin Centre closed due to flooding but re-opened by 1.30pm. Clarks and Primark closed in Bournemouth due to flooding. Waterstones shut its basement.

Poole bus station was 18 inches deep in water, but a spokesman for Wilts & Dorset said buses are still running, with some delays.

In Bournemouth buses struggled to manoeuvre along Gervis Place through water more than half-a-foot deep in places as their bedraggled customers sheltered from the rain.

Lower Charminster Road and Glenferness Avenue were flooded and closed.

Every fire crew in Dorset and Hampshire was either on standby or attending a flooding incident after torrential rain hit the region this morning.

Dorset Fire and Rescue Service received 50 calls in half-an-hour and calls were still coming in thick and fast from across the Poole and Bournemouth conurbation, said a spokesman.

Among flooding incidents fire fighters were attending were Asda at Springbourne, House of Fraser in Bournemouth, the Russell Cotes Museum and Bournemouth Nuffield Hospital where patients were being evacuated due to a collapsing ceiling.

“Our advice is to switch the electricity off at the mains,” said a spokesman.

“If there is flooding move to higher rooms and take any precious objects with you.

“If flood water is coming in call us, but it might take us some time to get to you.”

The first day of the Bournemouth Air Festival was also affected with daytime flying displays and Night Air cancelled due to the severe flooding in Bournemouth's Lower Gardens.

Thanks to all our readers who sent in pictures or video footage.

Echo reporting team: Stephen Bailey, Steven Smith, Joanna Codd, Julie Magee, Katie Clark, Diana Henderson, Harriet Marsh, Joanna Wright, Darren Slade.